Positioning and locking device for pushbutton controlled arrangements



Jan. 18, 1966 3,229,548 C. M. DU TEMPLE DE ROUGEMONT ET AL POSITIONING AND LOCKING DEVICE FOR PUSH-BUTTON CONTROLLED ARRANGEMENTS Filed June '7, 1963 W lli III! 10/! T ll III/II 111.0

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v//////////////;'777/7/'/7z""' II United States Patent Claims. (c1. 7s s27 This invention relates to a device for locating and locking in two specific positions a movable element sliding in a fixed frame element and influenced along the direction of sliding by resilient means.

The invention is applicable to all push-button controlled switching arrangements in which the transition from one to the other of two specific positions of the movable element is obtained by a pressure exerted on the said element, always in the same direction and against the action of resilient means. Such switching arrangements are employed for instance in keyor button-operated electric switchgears, and the invention relates also to switchgears of this kind incorporating such a locking device.

Many locking devices are already known in which the movable sliding element is associated with a guiding element of closed profile, for example notched or heart cam shaped, which is arranged to receive a retaining finger carried on the fixed frame or casing. The guiding element comprises at least two, V-shaped parts, the points whereof are identically directed and substantially parallel to the direction of sliding, the pointed elements respectively controlling, when engaged by the retaining finger, the two specific positions of the movable element.

In these known devices, the retaining finger is resiliently 7 attached on the fixed frame in such manner as to be able to move parallel to its axis when its end is engaged in the guiding element. Means are provided for causing this motion to be performed always in the same direction, this result being obtained by a particular design of the heart cam, or by varying the depth of the cam notch to form bevels and stops preventing the return of the finger backwards.

In such devices, the retaining finger must be fitted on an arm movable with reference to the frame, usually pivoting with respect to'the latter, and always remaining parallel to its own axis.

The present invention provides a device for the purpose aforesaid, in which the retaining finger is not constrained to remain parallel to its own axis but can on the contrary swing freely when its end engages the guiding element.

Such a device appreciably simplifies the manufacture and assembly of lockable push-buttons, in particular by the elimination of a supporting arm as aforesaid, the finger being held in position merely by a spring, which makes economical mass production possible.

The present invention is a device for the purpose aforesaid, wherein one of the elements incorporates a guide track of the heart cam type, the bottom whereof has bevels and stops, and wherein the other element incorporates retaining means, a part whereof co-acts with the guide track, the retaining means incorporating a cylindrical pin, whereof one end engages in the guide track, a resilient plate or blade attached to the other element and bearing on the other end of the said pin, and an aperture for the passage and pivoting of the pin at least in a plane substantially perpendicular to the direction of sliding.

The guiding notch or heart cam is preferably cut out of the sliding element, for instance in the selector gear of an electric switch, the hole in which the pin pivots being made in the fixed frameand the fiat surface resil iently bearing on the second end of the said pin consisting of a leaf spring fitted on the fixed frame. A cam of slightly asymmetrical plan form is to be preferred as enabling the stroke of the sliding element to be shortened and thus reducing the longitudinal extension of the switch arrangement.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawing, in which:

FIG. 1 is a perspective view partly in section, of a device in accordance with the invention applied to a button-operated electric switching arrangement;

FIG. 2 is a plan view of the selector element of the switch arrangement according to FIG. 1;

FIG. 3 is a sectional view of the switch arrangement along the line III-III of FIG. 2; I

FIG. 4 is a cross-sectional view along the line IV- of FIG. 3.

The electric switching arrangement comprises a selector element 2 carrying movable contacts and sliding in a fixed frame carrying fixed contacts connected with current taps 6. A spring 8 surrounding the end of the'selector element bears against the fixed frame and a button 10 and urges the selector element continuously to move out of the fixed frame.

The selector element 2 incorporates a hollow cam notch 12 with a closed contour, either symmetrical or asymmetrical, having two points or peaks 14 and 16 (FIG. 2) and the depth whereof is variable to form several bevels and stops 18, 18 and 18", which cause a retaining finger to move along the guiding profile always in the sense of the arrow 20. The retaining finger is formed by a simple pin 22 (FIGS, 3 and 4) which is elastically held against the bottom of the cam notch by a leaf spring 24 attached to the frame 2, the spring 24 exerting on the pin 22 a force directed as indicated by arrow 26 in FIG. 3.

In the region of its free end, the leaf spring 24 has at least one partially plane surface substantially perpendicular to the direction 26, along which the upper end of the pin 22 can slide freely.

The pivoting of the pin in the fixed frame is obtained by passing the pin 22 through a hole 28 in the frame. The shape and size of this hole are such that the pin 22 can oscillate freely in a plane substantially perpendicular to the direction of sliding when its lower end is travelling along the cam profile 12. FIG. 4 shows the inclined position assumed by this pin when its end is for instance in the position 30 shown in FIG. 2. On .the contrary, in the plane parallel to the direction of sliding, the pin 22 is only free to oscillate restrictedly in the hole 28 and in that direction the diameter of the hole 28 is only slightly greater than the thickness of the pin. To summarize, the hole 24 may be of substantially rectangular form and preferably has bevelled edges 32.

The operation of the abovedescribed arrangement is as follows:

When the selector element 2 is in the position corre sponding to the depression of the button 10 (FIG. 3), the end of the pin 22 is in the position 34 (FIG. 2) in the cam notch 12, and holds the selector element in this position, against the force of the spring 8, by engaging in the notched part of the central bar 36 which is located opposite the point or peak 16 of the heart cam. In this position, the pin 22 is braced against the edges of the hole 28 and owing to the play necessary for fitting the pin in the hole, assumes the slightly inclined position shown in FIG. 3.

When the but-ton 10 is depressed, the end of the pin is prevented from returning backwards by the bevel 18' and therefore moves in the direction of rotation of the arrow Patented Jan. 18, 1966 20 towards the position 38, the pin being able to slant freely owing to the side play permitted by the shape of the hole 28.

I When the button is released, the selector element moves back under the influence of the spring 8, which causes the end of the pin 22 to follow the whole upper branch of the cam notch 12 (FIG. 2) and lodge in the depression formed by the peak 14 of the cam profile, which determines the second positon of the selector element. The pin, the inclination whereof has been changing while travelling along this path, resumes a position identical with that shown in FIG. 3, and keeps the selector element locked against the action of the spring 8.

The bottom of the cam notch is sloped along the entire upper arm as above, and ends in a bevel 18 which prevents the pin from returning backwards when the button 10 is again pressed.

When the end of the pin travels along the lower branch of the cam profile (FIG. 2) the pin tilts again, but in the opposite direction and, when passing through the position 30, the pin assumes its maximum slant as shown in FIG. 4. At the end of this lower branch, the bevel 18" at the bottom of the cam notch causes the end of the pin to return towards the position 34.

It will thus be seen that by means of the present invention, the pin does not require any pivoting supporting arm so that the number of components required is reduced and the bulk of the arrangement is less.

In accordance with one advantageous embodiment, the leaf spring 24 is simply held in place on the frame by the pressure of the spring 8 without any connecting screw or rivet, and is prevented from becoming loose by a reverse nose 40 which engages between the frame and the selector element.

Since, contrary to known locking devices using a cam notch, the retaining finger does not remain parallel to itself but inclines in one or the other direction along the cam profile, the central core 36 of the heart-shaped cam is preferably made conical (FIG. 4) which enables pro-per guiding of the pin, while in previous cams, the sides thereof for-med cylindrical surfaces, which would prevent the free oscillation of the pin in an arrangement according to the present invention, or would at least require a considerable play between the pin and the guiding track.

As an example, a cam has been shown of heart shape, but it is obvious that many other cam shapes may be suitable, symmetrical or preferably asymmetrical, which enables a shorter stroke of the selector element, either with or without rectilinearsections. The cam profile may be moulded, as may be the selector element, from a synthetic plastic material.

We claim:

1. A device for the purpose aforesaid, wherein one of the elements incorporates a guide track of the heart cam type, the bottom whereof has bevels and stops, and wherein the other element incorporates retaining means, a part whereof coacts with the guide track, the retaining means incorporating a cylindrical pin, whereof one end engages in the guide track, a resilient plate or blade attached to the other element and bearing on the other end of the said pin, and an aperture for the passage and pivoting of the pin at least in a plane substantially perpendicular to the direction of sliding.

2. A device in accordance with claim 1, for use with a button-controlled electric switching arrangement, wherein the heart cam is carried on a sliding selector element which carries moving contacts, and wherein the aperture allowing the passage and pivoting of the retaining pin is formed in an element integral with a fixed frame carrying fixed contacts, and wherein the resilient blade holding the pin against the bot-tom of the said cam track is attached to the fixed frame.

3. A device in accordance with claim 2, wherein the resilient blade is held on the fixed frame by means of a spring forcing the movable element in the direction of sliding.

4. A device for securing an operating member in alternating successively different rest positions following successive operations thereof in the same direction, comprising (a) a fixed frame element having an aperture therein,

(b) an operating member slidable in said frame element,

(c) resilient means urging said operating member in one direction relative to said frame element,

(d) a closed-loop guiding cam track formed on said operating member and defining rest positions thereof spaced in the direction of its sliding movement,

(e) a control pin mounted loosely in said aperture and extending at one of its ends into said cam track, and

(f) spring means carried by said frame and having a flat surface engaging the other end of said pin to urge the same generally towards said cam track without impeding limited rocking motion of the pin in the aperture.

5. A device in accordance with claim 4, in which said aperture is a bevel-edged rectangular aperture having its longer dimension perpendicular to the sliding direction of said operating member.

References Cited by the Examiner UNITED STATES PATENTS 2,592,660 4/1952 Crumley 74-527 X 2,946,237 7/1960 Hebert 74527 BROUGHTON G. DURHAM, Primary Examiner. 

4. A DEVICE FOR SECURING AN OPERATING MEMBER IN ALTERNATING SUCCESSIVELY DIFFERENT REST POSITIONS FOLLOWING SUCCESSIVE OPERATIONS THEREOF IN THE SAME DIRECTION, COMPRISING (A) A FIXED FRAME ELEMENT HAVING AN APERTURE THEREIN, (B) AN OPERATING MEMBER SLIDABLE IN SAID FRAME ELEMENT, (C) RESILIENT MEANS URGING SAID OPERATING MEMBER IN ONE DIRECTION RELATIVE TO SAID FRAME ELEMENT, (D) A CLOSED-LOOP GUIDING CAM TRACK FORMED ON SAID OPERATING MEMBER AND DEFINING REST POSITIONS THEREOF SPACED IN THE DIRECTION OF ITS SLIDING MOVEMENT, (E) A CONTROL PIN MOUNTED LOOSELY IN SAID APERTURE AND EXTENDING AT ONE OF ITS ENDS INTO SAID CAM TRACK, AND (F) SPRING MEANS CARRIED BY SAID FRAME AND HAVING A FLAT SURFACE ENGAGING THE OTHER END OF SAID PIN TO URGE THE SAME GENERALLY TOWARDS SAID CAM TRACK WITHOUT IMPEDING LIMITED ROCKING MOTION OF THE PIN IN THE APERTURE. 